An: 2014, Nr.3, Articol Nr. 10

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      LUNG DEVELOPMENT OF THE FETUS (Abstract): Purpose: The lung structures are formed in parallel following several successive stages of development: embryonic phase, pseudoglandular phase, canalicular phase, saccular phase, alveolar phase. Finally the following structures are finalized: bronchi, bronchioles, blood vessels lung parenchyma, that can be functional only after the secretion of surfactant. Starting from these data we have tried to objectify the lung development during fetal life. Material and Method: In order to highlight the fetal lungs we used parasagittal sections on mice fetuses with the cephalic-caudal dimensions of 30 mm, which corresponds to the ontogenetic time of the 3rd trimester of gestation. Results: For each lung we can describe a base a diaphragmatic surface, a tip and tow surfaces: costal and mediastinal. Discussions: The respiratory segment is formed from bronchi of different structures and caliber. We have observed large bronchi and than bronchi in diferent stages of dicotomization. The small bronchi have in their wall structure peripheral myoblasts, with elongated shape acidophil cytoplasm and central nucleus. The covering epithelium is cylindrical simple. The bronchioles are coated with simple cubic epithelium. The middle tunica can poorly identified by the presents of a few myoblasts and the adventitia is missing. Conclusions: Microscopic aspect of the lungs is pseudoglandular. The bronchi’s wall is undergoing differentiation. Vessels have similar structure to the one of the adult.

Key words: EXPERIMENTAL STUDY, FETAL LUNG, LUNG DEVELOPMENT, PSEUDOGLANDULAR PHASE.